This invention relates to a low profile air conditioning unit for installation upon the roof of a vehicle and, in particular, upon the rooftop of a passenger bus.
Rooftop air conditioners have been installed upon buses and the like for a number of years. Typically, both the condenser and the evaporator sections of the unit are mounted outside the passenger compartment of the vehicle upon the roof. Conditioned air from the unit is passed into the vehicle through an opening in the roof and return air is passed back into the unit through a second roof opening. The compressor servicing the unit is generally located in the engine compartment of the vehicle and is driven directly from the engine. Refrigerant lines are passed back from the engine compartment to the rooftop unit through the interior of the vehicle. These interior lines can pose a constant danger due to the lines leaking or sweating.
In U.S. Pat. No. 4,870,833 there is disclosed a rooftop air conditioning unit for a motor vehicle that utilizes an electrical driven compressor that is contained along with an inverter in the rooftop unit. Power to the unit is provided by a generator that is driven directly from the engine of the vehicle. In this arrangement the refrigerant lines passing between the engine compartment and the air conditioning unit are eliminated thus avoiding any danger of the lines leaking or sweating inside the vehicle. However, the removal of condensate from the rooftop unit itself still poses a problem.
A window air conditioner is described in U.S. Pat. No. 5,337,580 in which an axial flow condenser fan is mounted with the condenser coil and the compressor in the outdoor section of the unit. The evaporator coil is contained in the indoor section of the unit. A cone shaped condensate slinger is connected to the condenser fan motor and is arranged to throw condensate generated by the indoor evaporate coil against the outdoor condenser coil. A portion of the condensate that contacts the heated surfaces of the condenser coil is evaporated to improve the efficiency of the unit. The remaining condensate is collected in the condenser pan and is permitted to drain as moisture to the outdoors discharges from the unit as a vapor in the cooling air stream.
Many rooftop air conditioning units that are mounted on buses or recreational vehicles simple drain the condensate from the evaporator over the roof of the vehicle or multiple drain lines requiring costly installation and maintenance. The moisture, over a period of time forms an unsightly stain on the vehicles finish and films the window surfaces reducing the drivers visibility and thus posing a potential hazard. Attempts to incorporate more effective condensate removal systems for these types of roof top units invariably produce an increase in the height of the unit which, in turn, increase the amount of drag acting on the vehicle as it moves through the air.
It is a primary object of the present invention to improve rooftop air conditioning units for vehicles and, in particular, for buses, recreational vehicles and the like.
It is a further object of the present invention to more efficiently remove condensate from a rooftop air conditioning unit of a motor vehicle.
Another object of the present invention is to provide an effective way of removing condensate from a rooftop air conditioning unit that contains multiple evaporator coils and condenser coils.
A still further object of the present invention is to provide an efficient condensate removal system for a rooftop air conditioning unit for a bus or the like without having to increase the height and size of the unit.
Yet another object of the present invention is to remove condensate from the rooftop air conditioning unit of a bus in a clean and an aesthetically pleasing manor.
Yet another object is to eliminate installation and maintenance of condensate hoses and connections.
These and other objects of the present invention are provided by a rooftop air conditioning unit that includes multiple evaporator coils and condenser coils. An enclosure is mounted adjacent to the evaporator section of the unit that contains a pair of vertical side walls and a pair of opposed condenser coils that form the end walls of the enclosure. The enclosure further includes a bottom wall and a top wall that has an opening for housing a condenser fan. The fan is connected to the drive shaft of a fan motor which is suspended inside the enclosure. The drive shaft of the motor is aligned along the central axis of the enclosure and a slinger dish is mounted beneath the motor and is secured to the shaft. The bottom wall of the enclosure slopes inwardly for the side wall and end walls of the enclosure toward the central axis of the enclosure. Condensate generated by the evaporator coils is conducted into the enclosure and collects in the center of the enclosure beneath the slinger dish. The slinger dish opens upwardly towards the motor and contains a suction port for the drawing condensate collected in the center of the enclosure into the dish. A series of distribution ports direct the condensate over the inside surface of the dish and the condensate is then broadcast outwardly over the surfaces of the two condenser coils. The condenser coil are placed at an acute angle with regard to the central axis of the enclosure to considerable reduce the height of the unit. Preferably, each coil forms an angle of between 40xc2x0 and 50xc2x0 with the central axis of the enclosure.